1. Field of the Invention
The present invention relates to a camera, and more particularly to a camera having a safety lock mechanism for locking a lid of a cartridge chamber.
2. Description of the Related Art
Various kinds of photo film cartridges called as the IX-240 type are put on the market. As to such photo film cartridge, a photo film having a smaller picture size are contained, up to its leading edge, in a cartridge body which is smaller than a film cassette of the 135 type. This film cartridge has a film advancing mechanism and a light shielding lid incorporated therein. The film advancing mechanism advances the photo film through a film mouth by rotating a spool. The light shielding lid opens and closes the film mouth.
Moreover, in the photo film cartridge of the IX-240 type, is incorporated an indication mechanism for indicating a usage state of the contained photo film. This indication mechanism comprises four openings and an indication plate. The four openings are formed in an edge face of the cartridge body and have different shapes. The indication plate is integrally rotated with the spool behind the openings. Usage states of an unused state, a halfway state, an exposed state and a developed state are assigned to the respective openings. The usage state corresponding to the opening through which the indication plate is visible is adapted to represent the current usage state of the photo film. With respect to the indication mechanism for the usage state, setting the indication is performed such that after the whole photo film has been rewound in the cartridge body, the spool is successively rotated in a film rewinding direction to control a stop position of the spool. In other words, a camera loaded with the above-noted photo film cartridge includes a usage-state setting mechanism for carrying out a VEI (Visual Exposure Indicate) process. In the VEI process, the spool is successively rotated in the rewinding direction after rewinding the whole photo film into the cartridge body, and then, the usage-state indication plate is set to a position corresponding to the usage state of the cartridge.
On the other hand, various cameras using the photo film cartridge of the IX-240 type are sold. Such camera comprises a cartridge chamber for containing the photo film cartridge, a cartridge-chamber lid for opening and closing the cartridge chamber, a chamber-lid operation mechanism for operating the cartridge-chamber lid, and a safety lock mechanism for locking the chamber-lid operation mechanism. Further, the camera comprises an advancement mechanism for advancing the photo film by rotating a spool of a cartridge body contained in the cartridge chamber, and a light-shielding-lid operation mechanism for operating the light shielding lid of the cartridge body.
Examples of the above-mentioned safety lock mechanism are described in Japanese Utility Model Laid-Open Publication No. 2-21634 and in Japanese Patent Laid-Open Publication Nos. 5-232560 and 7-199305 (counterpart of U.S. Pat. No. 5,600,393). In the above publication No. 2-21634, a lock member is frictionally engaged with a rotational member whose rotational direction at the time of film winding is different from the rotational direction at the time of film rewinding. When the photo film is wound up, the lock member is moved to a lock position where the chamber-lid operation mechanism is locked. When the photo film is rewound, the lock member is moved to a release position where the lock is released. Meanwhile, in the above-noted publication No. 7-199305, it is detected that the photo film is drawn out of the cartridge body, and in accordance with this detection, the chamber-lid operation mechanism is locked. Further, in the above-noted publication No. 5-232560, the lock member for locking the chamber-lid operation mechanism is driven by using an electromagnet.
However, with respect to the safety lock mechanism described in the above-noted publication No. 2-21634, the chamber-lid operation mechanism is not locked at the time of film rewinding so that it is likely to expose the photo film by mistakenly opening the cartridge chamber during the film rewinding. Moreover, if the cartridge-chamber lid is opened when the indication mechanism for indicating the usage state sets the indication of the usage state, there arises a problem in that the wrong indication of the usage state is set.
Regarding the safety lock mechanism described in the above-noted publication No. 7-199305, although the cartridge-chamber lid can be locked when the photo film is rewound, there arises a problem in that a mechanical interlock mechanism becomes large so that downsizing the camera is difficult. Moreover, when the indication of the usage state is set, the photo film is not detected at the outside of the cartridge body. Thus, there arises a problem in that the cartridge-chamber lid is likely to be opened.
Regarding the safety lock mechanism described in the above-noted publication No. 5-232560, there arise problems in that a space for incorporating the electromagnet and an actuator is necessary, and electric power is greatly consumed.
In view of the foregoing, it is a primary object of the present invention to provide a camera having a safety lock mechanism in which a lid of a cartridge chamber is prevented from being mistakenly opened during a film conveying operation without regard to film winding, film rewinding, and setting by a usage-state indicating mechanism.
It is a second object of the present invention to provide a camera having a safety lock mechanism in which its size is reduced and electric power is not wasted.
It is a third object of the present invention to provide a camera having a safety lock mechanism in which safety lock is released by simple structure without changing an indication of a usage state of a photo film cartridge.
In order to achieve the above and other objects, the camera according to the present invention comprises a winding-up lock mechanism and a rewinding lock mechanism which prevent a lid of a cartridge chamber (hereinafter, cartridge-chamber lid) from being opened.
In a preferred embodiment, a chamber-lid operation mechanism for operating the cartridge-chamber lid includes an operation member, an engagement lever and an intermediate lever. The operation member is slidably attached to a camera body. The engagement lever engages with the operation member and is swung in association therewith to open the cartridge-chamber lid. The intermediate lever is coupled to the engagement lever and abuts on the winding-up lock mechanism and the rewinding lock mechanism. The chamber-lid operation mechanism is changed between a retaining state for keeping the cartridge-chamber lid in a closed position, and a release state for releasing the cartridge-chamber lid.
When a film conveying mechanism starts to wind up a photo film, the winding-up lock mechanism abuts on the intermediate lever to set the chamber-lid operation mechanism in the retaining state. When the film conveying mechanism starts to rewind the photo film, the winding-up lock mechanism is changed not to abut on the intermediate lever so that the chamber-lid operation mechanism is set in the release state.
Meanwhile, when the film conveying mechanism starts to rewind the photo film, the rewinding lock mechanism abuts on the intermediate lever to set the chamber-lid operation mechanism in the retaining state. When the film conveying mechanism starts to wind up the photo film, the rewinding lock mechanism is changed not to abut on the intermediate lever so that the chamber-lid operation mechanism is set in the release state.
Incidentally, when a photo film cartridge is removed from the camera body after rewinding the photo film, both of the winding-up lock mechanism and the rewinding lock mechanism set the chamber-lid operation mechanism in the release state.
In another embodiment, a drive gear and a spool driving member are provided above the intermediate lever. The drive gear is rotated in a forward direction at the time of film winding and is rotated in a reverse direction at the time of film rewinding. The spool driving member is rotated together with the drive gear to rotate a spool of the photo film cartridge in either of a film winding-up direction and a film rewinding direction.
Between the drive gear and the spool driving member, is disposed a press member for keeping them in a non-contact state within a predetermined region. A part of the press member is bent downward so as to press the top of the press member against an upper face of the spool driving member.